provision.sh: Docker proxy defaults to registry-1.docker.io (works directly
from VPS). Set DOCKER_MIRROR_URL/USER/PASS env vars to route through
docker-mirror.liara.ir once Liara credentials are obtained.
update-docker-upstream.sh: swap Docker proxy upstream at any time without
re-running the full provision (useful after getting Liara credentials).
indexType auto-selects: HUB for docker.io direct, REGISTRY for Liara/Harbor.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>